ALBUQUERQUE, N.M. – The federal government’s only underground nuclear waste dump remained shuttered Monday and state environment officials said they have set deadlines for the U.S. Department of Energy and its contractor to deal with radioactive waste left above ground at the repository.

Dozens of drums and other special containers that have been shipped to the Waste Isolation Pilot Plant from federal facilities around the country are being stored in a parking area at the plant and inside the facility’s waste handling building.

From there, the waste is usually taken to its final resting place deep in underground salt beds. However, the repository has been closed since early February due to back-to-back accidents, including a radiation release that exposed at least 13 workers and set off air monitoring devices around the plant.

Under its permit with the state, the dump can keep waste stored in the parking area for only 30 days and up to 60 days in the handling building. Due to the closure, the state is extending those deadlines to 60 days and 105 days, respectively. The federal government would have to develop an alternative storage plan if the underground dump remains off-limits for more than three months.

The Environment Department outlined the deadlines, along with requirements for weekly reports and a mandatory inspection before operations resume, in an administrative order made public Monday.

Jeff Kendall, general counsel for the department, said state officials believe allowing a little more time to fully vet all the options for safely storing the waste is the best bet.

“To require them to begin to systematically ship particular waste units back to points of origin or back to particular locations in a rather expedited fashion was not the best thing as far as environmental health or human health in this instance,” Kendall said in a phone interview.

Kendall added that the order also gives the state more explicit oversight as to what happens with the waste and how things are being handled by DOE and the plant managers.

After 15 years of operating with a stellar record, a truck that officials said was hauling salt in the underground chambers caught fire Feb. 5, shuttering the plant and halting all waste shipments. Nine days later, a radiation alert activated in the area where newly arrived waste was being stored.

Tests are ongoing to determine the health effects for the workers, and officials have yet to determine what may have caused the leak. They have been unable to access the underground portion of the repository.

Donavan Mager, a spokesman for Nuclear Waste Partnership LLC, which runs WIPP, said Monday onsite monitoring and sampling of the surrounding soil, vegetation and water continue. He said new results are expected in the coming days.

WIPP officials confirmed Monday that only 13 employees were onsite when the radiation release occurred late Feb. 14. Another 140 employees showed up for work the following day.

Now, there are only 80 essential workers on site. Mager said they’re working in areas that have been tested and are free of contamination.

Some areas have been designated as “radiological buffers,” where only trained radiological workers can go. Mager said those workers are wearing protective equipment.

Every time workers leave the site, Mager said they are checked for any contamination.

WIPP is the nation’s first underground nuclear repository and the only facility in the country that can store plutonium-contaminated clothing and tools from Los Alamos National Laboratory and other federal nuclear sites.

Since opening, the plant has received more than 11,890 shipments, totalling more than 90,000 cubic meters of waste.

The above-ground material targeted by the state Environment Department’s order includes 145 cubic meters of waste in containers of various sizes and shapes.